1. Field of The Invention
The invention relates to connector assembly, especially to two connectors aligned and juxtaposed with each other and having different pitches with their respect contact arrangements.
2. The Prior Art
As shown in FIG. 1 and in U.S. Pat. Nos. 4,080,027, 4,288,139, 4,327,954 and 4,826,447, the conventional card edge connector includes an elongated insulative housing having a central slot lengthwise, two rows of contacts oppositely positioned along proximate two sides of the slot, respectively, for electrical engagement with the conductive pads on the lower edge portion of the board which is inserted into the slot. As shown in FIG. 2 and in U.S. Pat. Nos. 4,846,734, 4,934,961, 4,993,972, 5,024,609, 5,035,632, 5,156,554 and 5,156,554, the advanced card edge connector includes the similar housing structure for reception of a board, but generally has vertically or horizontally staggering contact arrangement by each side along the slot. This method allows for high density or small or half pitch contact arrangement for the card edge connector which facilitates the high speed and high quantity of the signal transmission within a computer to meet the requirements of the recent industry. It can be understood that due to the difficulties of manufacturing, the high density contact arrangement connector is much more expensive than the low density contact arrangement connector. It is also noted that though high density (fine pitch) contact arrangement is popularly used within the computer today, the traditional low density (regular pitch) contact arrangement connector still exists within the same computer because these two different pitch contact arrangement connectors are configured to function to accommodate the different inserted boards for different specific purposes to some of which the high density contact arrangement of the connector may not be required for cost-saving consideration.
In the recent trend, for the increasing competition and the reduced beneficial rate in the personal computer industry, the computer manufacturer is now trying every possible step to lower the cost for survival. Some of them have intentionally had these two different type connectors lengthwise aligned and juxtaposed with each other as a connector assembly, then using a larger unitary board which has two divided regions on its lower edge portion having different pitch arrangements of the conductive contacts thereabout, respectively, for corresponding reception within these two aligned but different type connectors, respectively. Through this attempt, one board incorporating two different type connectors replaces two boards incorporating two different type connectors, so it may save considerable expense in the boards' cost which is of the high percentage in the manufacturing cost of the computer. Even though this effort seems successful from the general viewpoint, some disadvantages may occur simultaneously.
It can be contemplated that the different density arrangements of the contacts of the connectors will result in different retention forces which act on these two different type connectors, respectively. It means that the insertion force or the withdrawal force of the lower edge portion(s) of the board(s) within these two different type connectors will be different from each other in the same unit length. In the conventional situation, using two separate boards incorporating these two different connectors has no problems. While, using only one board with divided two regions of the lower edge portion incorporating two different type connectors induces an intention of rotation of the board during simultaneous insertion or withdrawal of the board with regard to these two different type connectors due to the unbalanced and unequal forces being derived within these two different type connectors for the sake of the different pitch arrangements of the contacts therein. In other words, the friction force in the high density contact arrangement connector is much higher than that in the low density contact arrangement connector, and the board intends to rotate about the outer end of the high density contact arrangement connector during its insertion or withdrawal with regard to this connector assembly. This phenomenon is paid attention to by the computer manufacturer, and a rotation handling section is designedly positioned on one side of the board, which can be protrusively positioned about the outer end wall of the low density contact arrangement connector. Hence, the operator can easily hold that handling section to rotatively insert or withdraw the unitary board with regard to the connector assembly. This additional handling section facilitates the insertion and the withdrawal of the board with regard to the connector assembly, but ignores some limitations of the connector assembly itself.
It is popularly understood that for a conventional connector with regardless of either a high density or a low density contact arrangement, the incorporating board is perpendicularly inserted into or withdrawn from the connector housing, so that the transverse end walls or the partition wall for strength reinforcement are all designed to accommodate the inserted board in a perpendicular movement or access relation. In other words, the dimensions and the tolerances of these portions are not suit for any improper rotation movement of the board thereabout.
Referring top FIG. 3, a low density contact arrangement connector 10 and a high density contact arrangement connector 20 are aligned and juxtaposed with each other as a connector assembly on a mother board 3 and a unitary daughter board 4 is intended to incorporate these two connectors 10 and 20 simultaneously. The daughter board 4 has a series of, contacts 42 of a low density arrangement along a first region 42' of the lower edge portion and a series of contacts 43 of a high density arrangement on the second region 43' of the same lower edge portion thereof. A handling section 44 is positioned on one side of the board 4 which is close to the outer end of the low density contact arrangement connector 10. A recess 40 is positioned between the group of contacts 42 and the group of contacts 43 for receptively straddling two respective inner ends of these two connectors 10 and 20. The board 4 further comprises at least two indents 41 for respectively receiving the partition walls (not shown) of the connectors 10 and 20 each of which is positioned in the middle portion of connector, providing strength reinforcement and polarization. FIG. 4 discloses the rotation movement of the board 4, by means of the handling section 44, with regard to the connectors 0 and 20. And FIG. 5 shows a left portion of the connector 20 where the top portion 22 of the end wall 21 and the top portion 24 of the middle partition wall 23 may interfere with the board 4 during the rotation of the board 4 within the connector 20. This interference may cause structural crash around the end wall 21 or the partition wall 23 and make the whole connector 20 electrically or mechanically fail because the end walls 21 and the partition wall 23 provide the strength reinforcement for the whole structure of the connector 20.
Accordingly, an object of the present invention is to provide a connector assembly which has the advantage of unitary single board usage but without the risk of the structure failure to damage the electrical and mechanical contact between the connector assembly and the board.